Perpetual calendars



Aug. 23, 1966 w. c. BoGGlss PERPETUAL CALENDARS 2 Sheets-Sheet 1 Filed Nov. 21, 1963 INVENTOR Aug 23, 1966 w. c. BoGGlss 3,267,596

PERPETUAL CALENDARS Filed Nov. 21, 1963 2 Sheets-Sheet 2 United States Patent O 3,267,596 PERIETUAL CALENDARS Walter C. Boggiss, 229 Berry St., Norwood, Winnipeg 6, Manitoba, Canada Filed Nov. 21, 1963, Ser. No. 325,423 11 Claims. (Cl. lil- 109) This invention relates to changeable monthly calendars, and is an imp-rovement over my United States Patent No. 3,90617,7l1, for Perpetual Calendars, dated January 23, 1 2.

In the above patent, a rectangular number plate is lengthwise slidable in a triangular-shaped casing, and an elongated masking plate is adjustably mounted on the lower part of the number plate, the two co-acting with a window in the casing, including indicia printed thereon, to selectively expose all possible number arrangements for a month, when the number plate is manually moved. At the same time, an endless belt passe-s through the casing, having month names thereon for selective exposure, and various locking mechanisms are employed to hold the calendar parts in their different positions. In practice, it was found that the above locking mechanisms were easily damaged by thoughtless operation of the calendar, the endless belt was expensive Aconstruction and inclined to jam, and later when considering production it was found that die and assembly costs would be extremely high.

The principal object of the present invention is: to provide a simplified perpetual calendar construction, wherein easily pre-cut, rectangular-shaped sheets can be printed and die finished with a minimum loss of material, and for quick assembly; and all said parts of `the assembly can ibe retained in their display positions by the use of a simple frictional-holding member, thus materially reducing printing time and expense, simplifying die requirements, and substantially reducing manufacturing costs all around.

A further object of the invention is: to slidably mount the masking plate and the number plate in nested relationship within the casing, and Isuch that the masking plate can be manually end-shifted to adjust both plates into all possible number arrangements at the casing window, thus simplifying assembly and operation of the calendar, and further reducing manufacturing costs.

A further object of the invention is: to create a pocket in 4the calendar casing during the formation thereof, and provide a foldable month tab for removable-reception in said pocket, the tab end projecting from the pocket to expose selected month names thereon, said tab carrying the holding member for frictionally locking the parts, when the tab is in the pocket, thus eliminating the previous expensive belt construction, and the locking mechanisms.

A further object of the invention is: to attach a finger grip at each end of the masking plate, for manual operation of same along the calendar casing, including the pushing of the number plate thereby, and such that said grips might also present stops for contact with the casing to limit the plate movements, thus further simplifying construction.

A further object of the invention is: to provide means for holding the number plate stationary on the casing, during specific movements of the masking plate thereon, to insure accurate registration of the plate numbers with the indicia on the casing.

Still further objects of the invention are: to assemble the calendar in a folded position, for proper application Patented August 23, 1966 of sealing adhesive thereto, including the sealing, thus materially saving assembly costs; the folded ycondition permitting reception of the calendar in a retaining envelope for compact quantity storage, or ease of carrying; and said calendar also provided with a movable locking flap for holding the calendar open, or for releasing the calendar to re-fold.

With the above important and other minor objects in view, which will become more apparent as the description proceeds, the invention consists essentially in the design, construction and arrangement of the parts hereinafter more particularly described, reference being had to the accompanying drawings, wherein like characters of reference indicate corresponding parts in the several lign-res, and wherein:

FIGURE 1 is a perspective view of the assembled calendar.

FIGURE 2 is a fiat layout of the calendar casing.

FIGURE 3 is la face view of the masking plate.

FIGURE 4 is a face view of the number plate.

FIGURE 5 is a face view of the month tab, before folding.

FIGURE 6 is an enlarged view of the wire clip for holding the calendar parts in place.

FIGURE 7 shows the masking plate receiving the number plate therethrough, as a sub-assembly.

FIGURE 8 is a perspective view of the month tab in a six-sided belt form.

FIGURE 9 is a perspective view of the same month tab, in flattened rectangular-shape, and receiving the holding clip, as a sub-assembly.

FIGURE 10 is an enlarged cross sectional view, taken on the line 10-10, in FIGURE 1.

FIGURE 11 shows a sectional folded view of the calendar casing, minus operable parts.

FIGURE 12 is an enlargement of the upper end of FIGURE l0, with the month tab removed, and showing the braking method for .restricting movement of the number plate, as well as the working positions of the plate stops.

A calendar casing 10 is layout shown in FIGURE 2. This casing is formed from a rectangular-shaped sheet, which can be easily pre-cut in quantity. This layout, at bottom cent-re, is provided with an arced cut-out 11, for a finger clearance, the top centre is shallow V-notched as at 12, while a square-cornered opening 13 is punched therethrough, in the middle, for a window. Day-of-theweek indicia 14 is printed across the casing, above the edge of this opening, a pair of spaced vertical slits 15 are provided slightly thereabove, and a semi-circle is cut therebetween to form a door 16. Line scoring across the casing is indicated by dotted lines, those 17, 18, 20, 21, 22 and 23 being upwardly pressed, while those 19 and 24 `are downwardly pressed, to permit the casing to fold into the triangular-shape shown in FIGURES 1 and 10. The door 16 hinges on the score lline 21.

A `rectangular-shaped masking plate 25 is shown in FIGURE 3. This plate is printed with vertical and horizontal lines 26 to form a grid, having a heavy zig-zag upper edge line 27. A pair of holes 28 and 29 are punched through the plate, one at each end of the grid, and the plate is lengthwise slit along the Zig-zag line, as best shown at 30 in FIGURE 7, to connect the holes 28 and 29. Each end of the plate is rear bendable on the dotted lines 31, so they can be swung against the back, and form linger grips 32. If desired, these grips could be aser/,59e

separately cut and secured to the back by adhesive, in the manner suggested at 33 in FIGURE 7. Their upper endscould be used as stops. The upper edge of this plate, at each end, is slightly cut downward, as at 34, to provide corner stops 35 and 36, while the central part is turned down rearwardly, on the dotted line 37, to form a friction flap 3S (see FIGURES 10 and 12).

A number plate is shown at 39 in FIGURE 4. This plate is relatively rectangular, except that the lower edge thereof is angularly cut, as at di). The bottom section 41 isradapted to be rearwardly turned up on the dotted line 42, and adhesively secured to the back, forreinforcement and a purpose later explained. The upper edge is cut downward slightly near 'each end, as shown at 43, to provide corner stops 44 and a5, while the central portion is turned down rearwardly on the dotted line, to form a further friction flap d6 (see FIGURES l0 and 12). The end corners of the stops L14 and 45 are cut olf at an angle, as at 4.7. A series of cross-cross lattice lines 48 are printedon the central face of this plate, and

they form open squares to receive a series of day-of-themonth numbers, from 1 to 31, as shown.

An unfolded rectangular month strip is shown at 49 in FIGURE 5. The names of the months are printed thereon in inverted pairs 50 down this strip, and the strip is scored thereacross between the paired months, as indicated at 51. Six holes 52 are also centrally punched through the strip, in the spaces separating the month pairs. This strip is later folded in a loop on the scored lines 51, to bring the two ends together in an endless sixsided belt, shown at 53 in FIGURE 8. The strip ends are then connected with a piece of adhesive tape, indicated at 54, and the extending tape ends (not shown) being cut off flush with the sides of the belt. By observing FIGURE 9, it will be seen that the belt can be ilattened into a rectangular month tab 55. Due to the hexagonal formation of the belt, it will also be apparent that it can be flattened at two other positions in the same manner, with different months at each end.

FIGURES 2 to 5 constitute all the ilat parts of the calendar, namely; the casing, the masking plate, the number plate, and the month tab strip, and all can be printed and die formed from rectangular blanks, which may be pre-cut in quantity, if so desired. It will also be seen, there will be very little waste of material.

The last part of the calendar is the formed wire clip 56, shown in FIGURE 6. The central part of the wire is turned in a circle 57, the two ends 58 are then brought close together, and pass centrally parallel down and across the rear of the circle, to a point past the periphery, in the form of legs. It will be appreciated that these legs will provide two contact points, and double clamping resiliency against material held between said legs and the circle 57, in a somewhat similar manner to the operation of a paper clip.

Before starting the assembly of the calendar, the nurnber plate 39 is passed through the zigzag slit Sil of the masking plate, to slidably nest therein, and form a subtassembly, as shown in FIGURE 7.` It will be noticed in this ligure, that only 28 days are showing for the month. This is because the number plate is stopped in the hole 29, at the far end of the masking plate. If the number plate is moved along the slit 36 toward the hole 28, the numbers 29, 30 `and 31 will progressively emerge from under the masking plate, and when the number plate nally stops in the hole 28, the number 32 thereon will be fully exposed. At the same time this plate subassembly is formed, the legs 5S of the clip 56 are passed through the two upper aligned holes 52 of the month tab 55, as a second sub-assembly, shown in FIGURE 9.

The assembling of the calendar is as follows: The punched and scored casing layout of FIGURE 2 is turned upside down, so the upper panel or flap 59 thereof will be at the bottom, and facing downward. The iirst subassembly, which comprises the nested plates of FIGURE 7, will now be placed downward, and over the lwindow 13, with the stops pointing toward the scored` line20, and such that portions of the lattice lines and grid thereon will be visible through the window. The ilap 59 of the casing will then be bent up and over on the scored line 17. Next, the second panel 60 will be similarly turned on the scored line 2G, and will be facing upward, with the folded ilap 59 thereunder. At this time, the door 16 will be positioned over the friction ap 46, and between the plates of the sub-assembly. Obviously, when this new second panel is bent on the line 20, the section 61, between the cuts or slits 15, will sink below the panel (itl, like a parallelogram, due to the offset score lines 18, 19 and 21. At the same time, the section 61, on each `side of the door 16, will press against the friction fia-p 38, which in turn wil-l press against and frictionally wrap the door 16 around the friction ap 46 (see FIG- URES l0 and 12). A brush or roller (not shown) is now passed over `the face of the panel 60, below an unmarked line about half-way between the lines 17 and 18, for application of a liquid adhesive thereto. In this operation, the roller will pass over, and not touch the section 61. If this is not possible, a held plate (not shown) could be temporarily inserted over this section to prevent the contact, and `hold the casing down. (Or the panel 60 could be provided with dry adhesive (not shown) which merely requires wetting to become operative.) The opposite end of the layout will now be Z- l folded on the score lines 23 and 24, and then brought bodily over, on the score line 22, and for contact of the other side of the panel 62 with the adhesive on the panel 60, to seal the two together. In this sealing, the panel 62 will cover the sunken section 61, and form a pocket 63 (FIGURES l0 and 11), which is open at the top of ythe calendar. The folding of the casing is clearly brought out in FIGURE l1, but due to an exaggerated bulging in the drawings, the nested plate sub-assembly of FIG- i URE7 is not shown. Actually, the material -of the casing, and of the parts, is sufciently thin for a fairly flat collapse of the casing folds.

When this folding is completed, and held fast by the adhesive, the `mere release of the folding pressure is generally sulhcient for the calendar to slightly open, such as the amount shown in FIGURE l1, and by inserting the forengers in the casing ends, the flap 59 can be swung down to open the calendar up, and its outer edge 64 can be caught in the corner 22 of the casing to maintain it open (see FIGURE 10). Accordingly, the calendar will firmly sit on its relatively wide bottom 65, with the front faces thereof at a good observable angle. Conversely, by again inserting the foretingers in each end of the casing and releasing the flap 59 from the corner 22, as shown in dotted outline, the calendar will collapse and re-fold, as shown in FIGURE ll.

In this connection it might be mentioned that the shall low V-notch 12 clears the central part of the edge 64 from contact with the masking plate at the slit 30, when said flap is lifted. The outer corner portions of the edge 64 also clear, as they ride over the turned-up portion 41 at the rear of the number plate. It will be seen that the portion il is level with the rear projecting portion of the masking plate (See FIGURE l0), so the ap 59 easily slips over the intersection.

In this sealed up assembly, the masking and number plates of the FIGURE 7 sub-assembly are slidably guided in the upper and lower front corners 21 and 22 respectively of the casing, and they can be operated, when the calendar is opened up, to selectively register the number columns on the number plate with the window indicia 14 for the correct first day of the month, and their overlapping can be changed, as previously explained, to vary the number of days in the month. These plates are prevented from escaping by the stops 35, 36, i4 or 45 contacting one or other of the cut edges of the sunken section 61 of the pocket.V When the stop 35 contacts this section, the number 1 of the number plate will be under and registering with the Saturday indicia of the casing. When the stop 36 contacts, the l will be registering with the Sunday indicia at the other side yof the window. When the hole-ZS-end of the slit 30 contacts the left hand end of the number plate, the inner sides of the stops 35 and 44 are aligned for joint further movement toward said section, and a full 31 days will be showing for the month at the window. When the hole-29-end of the slit 30 contacts the right hand end yof the number plate, the inner ends of the stops 36 and 45 are aligned for joint further movement toward said section, While 28 days will be showing at the window. If either end of the slit 3) is moved away from the number plate, as previously explained, the number of days in the month will change toward a 29 or 3() day showing at the window.

It should also be mentioned at this time that as the holes 28 or 29 of the masking plate approach the ends of the number plate, the upper stops 35 and 36 thereon pass the stops 44 or 45 respectively. The cut corners 47 of these latter stops insure they pass without interference.

The masking plate, when manually operated, slides past the number plate until an end of the slit 30 contacts therewith, after which it wil-l Ipush the number plate. By observing FIGURE 12 it -will be seen that the small semicircular door 16 is wrapped around the tia-p 46 of the number plate, while the masking plate presses against the bottom of this door to increase the pressure thereon, being assisted in doing so by the section 61 along which it rides, thus creating a rictional resistance on the number plate to restrict its movement, although the masking plate itself is relatively free. If the masking plate is now moved back, it wi-ll again slide past the number plate, in the opposite direction, until the other end of the slit 31 contacts. Accordingly, the manual pressure on the masking plate must be increased to overcome the resistance on the number plate, so the two plates can move together at these contacts. More friction can be exerted on the number plate if the diameter of the door 16 is enlarged. Accordingly, t-he number plate maintains fixed registration of its column numbers with the indicia on the casing, when the masking plate is free moving therepast.

After the casing and nested plates of FIGURE 7 have been assembled, as above described, the second sub-assembly, comprising the month tab and spring clip of FIGURE 9 is picked up with the thumb and foreiinger gripping the tab, just above the clip. The lower end of the tab is guided into the pocket 63, thumb controlling the spring clip and directing the -ring 57 thereof over the fold 21, to frictionally clamp the upper central edges of the masking and number plates in said fold, at this point, as well as holding the tab itself in the pocket. When the bottom of the pocket is reached, the upper end of the tab will still protrude, exposing the month name thereon (note top of FIGURES l and 10). All movable parts of the calendar are accordingly frictionally locked by the single spring clip.

In operation, the spring clip 56 will be released by partially or wholly withdrawing the month tab 55 from the pocket 63, as the caught legs of said spring clip will be pulled by the tab. Accordingly, the masking and number plates will be released for changing the month setting. The ends of the calendar are then grasped by thumbs and forengers, middle ngers entering the calendar ends fo-r contact with the grips 32 and thus operation of the masking plate. If the calendar is set for April, as shown in FIGURE l, and May is required, it is obvious, since April 30th is shown as a Thursday, that the tirst day of May must be a Friday. So, the masking plate is moved to the right, makes one idle space movement to expose the month number 3l, and bring the end of the slit 30 against the number plate. Both plates then jointly move until the l of the number plate is under and registering with the Friday on the casing indicia. As May has 3l days, and 3l days are showing, the setting is complete with the one movement, and just requires locking. If a less number of days were required, the operator would simply move the masking plate back, to cover the 3l, 30 or 29 as the case might be (the number plate being held stationary by the semicircular door 16 during this latter movement). No more than this back and forth movement of the masking plate is required for any setting. The spring clip is now removed from the month tab 55. The tab is then opened up and re-attened, between May and June and between July and August, with May showing at the top end. The legs of the spring clip are then inserted through the aligned holes 52 of the tab, just below May, and the tab re-placed in the pocket 63, as described. The setting for May is now complete.

The month tab 55 of FIGURE 9 has January showing at the top. By checking with FIGURE 5 it will be apparent that February must be directly therebehind, and March and April at the opposite end. So, no change of the attened tab is required for these months, other than turning the tab and inserting the spring clip properly. Actually, the tab need only be opened-up and re-tiattened when coming to the months of May, September and January, or three times a year.

While the previously described restricting action on the movement of the number plate is clearly brought out in FIGURE 12, the upper part of FIGURE 10 further shows how the same action is intensified by the spring clip, to frictionally lock both plates, as well as locking the month tab. It might also be mentioned at this time that, if the movable plates 25 and 39 are operated without Ireleasing the spring clip, and with suflicient pressure, they will move. However, the frictional resistance will warn the operator that he is not using the calendar correctly. The spring clip accordingly, is also a safety factor.

This calendar can be set to any month of any year, when the starting day of said month is known. A simple chart (not shown), listing the days on which months start for a number of years, could be printed on the back of the calendar for this purpose. The method of setting is quickly understood, as it is so simple. Changing the month tab is also quickly understood and appreciated, and it carries all the months, with practically no waste of space, The Well sloped angle of the front panel allows clear observation of its contents, while the wide base amply reduces tendency to tip. This base panel could carry instructions (not shown) for operation of the calendar. This still leaves the balance of the front panel, which presents a generous amount of space, for advertising or other display. And, as mentioned, the calendar can be easily released by simply lifting the ap 59 to collapse and fold for reception within an envelope. This will protect it against dirt and mutilation, and it will be compact for stacking, storage, or carrying in a Coat pocket.

What I claim as my invention is:

1. In a perpetual calendar: a casing having a window therein; a pair of plates slidable in said casing, for selective exposure of material thereon through said window, in the movement of said plates therepast; means for frictionally restricting the movement of one of said plates on the casing; means for manually moving the other of said plates past said restricted plate for a predetermined distance, to mask, and expose, specific material; and the other of said plates further operable, in the continued manual movement thereof at the end of said predetermined distance, to move the first mentioned one of said plates along the casing, against said restricting means.

2. In a perpetual calendar: a casing with a window therein; a plate having material thereon for exposure through said window; a second plate slidably mounted in said casing; said rst plate nested through a lengthwise slot in said second plate for a pre-determined movement of said plates past each other, to mask, and expose,

specific material on the first plate; means for rictionally holding the first plate stationary; and means for manually moving said second plate past said held first plate until one end f said slot contacts the held plate, and Vthen for endwise movement of said rst plate, by said second plate, against said frictional holding means.

3. In a perpetual calendar: a casing; a plate restrictively slide-mounted on said casing, and having number columns thereon; a second plate slidable on said casing; said number columns selectively exposed through a window in said casing by movement of said plates therepast, and past each other; a grip secured to each rear end of the second plate, for manual operation thereof, through the ends of the casing; stop means projecting above one of said plates for contact with the casing, to limit the sliding movement thereof on the casing; said second plate manually movable past said restricted first plate for a pre-determined distance, in one direction to mask specific numbers on said latter plate, and in the other direction to expose said specific numbers; means for joint movement of the plates, in the manual movement of the second plate past said pre-determined distance, and against said restricted first plate; and releasable clamping means for frictionally and jointly locking said movable plates stationary on the casing.

4. In a perpetual calendar: a triangular-shaped tubular casing having a window and a central pocket therein, with the opening to said pocket at the peak of the casing; a plate movable along said casing; a second plate manually slidable for individual movement along said casing, and for movement against said first plate at selected positions of said plates in relation to each other; columns of numbers on the rst plate for selective exposure through the window, in the movement of said plates therepast; a tab plate having the names of the months thereon; said tab plate receivable in said pocket, with one end thereof projecting from the opening, to selectively expose said month means; and releasable clamping means for frictionally holding all said plates stationary on the casing.

5. A perpetual calendar, comprising: a triangularshaped casing formed from a fiat layout; said casing having a front window and two centrally spaced slits therein; a pocket created between said slits in the formation of said casing, with an opening thereto at the peak of the casing; a number plate and a masking plate slidable in the upper and lower-front corners of the casing, and in relation to each other; columns of numbers on said number plate for selective exposure through the window, in the movement of said plates therepast; a grip secured on each end of the masking plate, for nger operation of i same along the casing; the upper end of each grip projecting above the masking plate, for Contact with one of the ends of the pocket, to limit the sliding movement of the masking plate; means for moving said plates past each other for three column spaces of said number plates, to mask, and expose, specific numbers thereon; means for jointly moving said plates, at each end of said three column spaces, in the manual operation of said masking plate; and a rectangular tab receivable in the pocket, and partially extending from the opening thereof, to expose a selected month name on the end thereof, from a list thereon.

6. In a perpetual calendar of the class described: -a casing; a number plate and a masking plate slidable in said casing for selective exposure of columns of numbers on said number plate through a window in said casing, in

the end-shifting movement of said masking plate; a pocket formed in the casing, with an upper entrance opening thereto; a corner-bent six-sided tubular tab having the names of the months thereon; said tab selectively attenfable, across opposing bent corners thereof, to form distinctive rectangular plates, each having different month names at the folded ends thereof; and said flattened tab receivable in said pocket, with one end thereof protruding from said opening, to expose a selected month name on the tab.

7. In a perpetual calendar: a triangular-shaped casing formed from a flat layout; said casing having a front wall with a window therein, a lengthwise indented rear wall, and a base; a number plate land a masking plate slidable in the upper and lower-front corners of said casing, and in relation to each other; means for selectively exposing columns of numbers on the number plate through said casing window, by manually end-shifting the masking plate along the casing, and selectively end-shifting the number plate thereby; a reinforcing section secured to the upper part of said indented rear wall and extending downwardly toward the base of the casing; a forward, swingable flap extending from the bottom of -said section, with the front edge thereof caught in the lower front corner of said casing, to hold said Casing in the triangular-shaped; and said flap manually releasable from said front corner, for Z-folding of the rear wall of the casing, between the indention and the lower rear corner, to collapse the rear wall and the base against the front wall of the casing.

8, In a perpetual calendar, wherein a pair of plates are both lengthwise slidable in the upper -and lower-front corner folds of a triangular-shaped casing, for selective showing of columns of numbers on one of said pl-ates through a window in said casing, by manual operation of the other of said plates; and wherein a rectangular-shaped tab having month names thereon is partially receivable in a pocket at the upper corner fold of the casing, for selective exposure of a month name on the protruding end thereof; a frictional locking means for said calendar parts, comprising: a wire clip having the ends thereof brought together as legs, and said legs `anchored through said tab; the central part of said clip formed in a circle to overlie said legs; and said central part sprung over the upper corner fold of the casing, to clamp the upper edges of said slidable plates within said latter fold, and also clamp said latter fold against the tab.

9. ln a perpetual calendar, wherein a pair of plates are lengthwise slidable in a casing for selective exposure of printed material thereon through a window of said casing by manual operation of said plates; said above calendar parts all formed from pre-cut rectangular sheets; one edge of one of said plates centrally notched to provide corner stops thereon; overlay strips secured on the opposing ends of the other of said plates, one at each end, to provide finger grips and further corner stops; the casing having an opening punched therethrough for said window; said casing having a pair of spaced slits therein defining an offset wall thereon; said casing scored at selected positions thereon, and folded on said scores, around said plates, with the offset wall positioned for contact of said stops therewith, in the movement `of said plates.

19. In a perpetual calendar', wherein a pair of plates are lengthwise slidable in a casing, for selective exposure of printed material thereon through a window in said casing, by manual operation of said plates; and wherein an exposure ltab is partially received in a pocket of said casing; the construction of said calendar, comprising: said parts all formed from pre-cut rectangular sheeting; corner stops provided on one of said plates; overlay strips on opposing ends of one of said plates to present linger grips thereon; the ends of the tab connected, to provide a sixsided tubing, which is selectively collapsible at opposing corners thereof, into distinct rectangles for reception in said pocket; an opening cut in the casing for said window; said pocket defined by a pair of parallel spaced slits in said casing; and said casing scored to fold triangularly around said plates, with a wall of said pocket positioned for contact of said stops therewith, in the movement of said plates along said casing. i y

11. In a perpetual calendar, wherein a pair of plates are lengthwise slidable in opposing guides on a casing, and for selective exposure of printed material thereon through a window in said casing, by manual operation of one of 1 0 References Cited by the Examiner UNITED STATES PATENTS 3,017,711 1/1962 Boggiss 40-109 5 JEROME SCHNALL, Primary Examiner.

EUGENE R. CAPOZIO, Examiner.

WENCELSO J. CONTRERAS, Assistant Examiner. 

1. IN A PERPETUAL CALENDAR: A CASING HAVING A WINDOW THEREIN; A PAIR OF PLATES SLIDABLE IN SAID CASING, FOR SELECTIVE EXPOSURE OF MATERIAL THEREON THROUGH SAID WINDOW, IN THE MOVEMENT OF SAID PLATES THEREPAST; MEANS FOR FRICTIONALLY RESTRICTING THE MOVEMENT OF ONE OF SAID PLATES ON THE CASING; MEANS FOR MANUALLY MOVING THE OTHER OF SAID PLATES PAST SAID RESTRICTED PLATE FOR A PREDETERMINED DISTANCE, TO MASK, AND EXPOSE, SPECIFIC MATERIAL; AND THE OTHER OF SAID PLATES FURTHER OPERABLE, IN THE CONTINUED MANUAL MOVEMENT THEROF AT THE END OF SAID PREDETERMINED DISTANCE, TO MOVE THE FIRST MENTIONED ONE OF SAID PLATES ALONG THE CASING, AGAISNT SAID RESTRICTING MEANS. 